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#include "device.h"

#include <qbluetoothaddress.h>
#include <qbluetoothdevicediscoveryagent.h>
#include <qbluetoothlocaldevice.h>
#include <qbluetoothdeviceinfo.h>
#include <qbluetoothservicediscoveryagent.h>
#include <QDebug>
#include <QList>
#include <QMetaEnum>
#include <QTimer>

Device::Device()
{
    discoveryAgent = new QBluetoothDeviceDiscoveryAgent();
    discoveryAgent->setLowEnergyDiscoveryTimeout(5000);
    connect(discoveryAgent, &QBluetoothDeviceDiscoveryAgent::deviceDiscovered,
            this, &Device::addDevice);
    connect(discoveryAgent, QOverload<QBluetoothDeviceDiscoveryAgent::Error>::of(&QBluetoothDeviceDiscoveryAgent::error),
            this, &Device::deviceScanError);
    connect(discoveryAgent, &QBluetoothDeviceDiscoveryAgent::finished, this, &Device::deviceScanFinished);

    setUpdate("Search");
}

Device::~Device()
{
    delete discoveryAgent;
    delete controller;
    qDeleteAll(devices);
    qDeleteAll(m_services);
    qDeleteAll(m_characteristics);
    devices.clear();
    m_services.clear();
    m_characteristics.clear();
}

void Device::startDeviceDiscovery()
{
    qDeleteAll(devices);
    devices.clear();
    emit devicesUpdated();

    setUpdate("Scanning for devices ...");
    discoveryAgent->start(QBluetoothDeviceDiscoveryAgent::LowEnergyMethod);

    if (discoveryAgent->isActive()) {
        m_deviceScanState = true;
        Q_EMIT stateChanged();
    }
}

void Device::addDevice(const QBluetoothDeviceInfo &info)
{
    if (info.coreConfigurations() & QBluetoothDeviceInfo::LowEnergyCoreConfiguration) {
        auto d = new DeviceInfo(info);
        devices.append(d);
        setUpdate("Last device added: " + d->getName());
    }
}

void Device::deviceScanFinished()
{
    emit devicesUpdated();
    m_deviceScanState = false;
    emit stateChanged();
    if (devices.isEmpty())
        setUpdate("No Low Energy devices found...");
    else
        setUpdate("Done! Scan Again!");
}

QVariant Device::getDevices()
{
    return QVariant::fromValue(devices);
}

QVariant Device::getServices()
{
    return QVariant::fromValue(m_services);
}

QVariant Device::getCharacteristics()
{
    return QVariant::fromValue(m_characteristics);
}

QString Device::getUpdate()
{
    return m_message;
}

void Device::scanServices(const QString &address)
{
    // We need the current device for service discovery.

    for (auto d: qAsConst(devices)) {
        auto device = qobject_cast<DeviceInfo *>(d);
        if (!device)
            continue;

        if (device->getAddress() == address )
            currentDevice.setDevice(device->getDevice());
    }

    if (!currentDevice.getDevice().isValid()) {
        qWarning() << "Not a valid device";
        return;
    }

    qDeleteAll(m_characteristics);
    m_characteristics.clear();
    emit characteristicsUpdated();
    qDeleteAll(m_services);
    m_services.clear();
    emit servicesUpdated();

    setUpdate("Back\n(Connecting to device...)");

    if (controller && m_previousAddress != currentDevice.getAddress()) {
        controller->disconnectFromDevice();
        delete controller;
        controller = nullptr;
    }

    if (!controller) {
        // Connecting signals and slots for connecting to LE services.
        controller = QLowEnergyController::createCentral(currentDevice.getDevice());
        connect(controller, &QLowEnergyController::connected,
                this, &Device::deviceConnected);
        connect(controller, QOverload<QLowEnergyController::Error>::of(&QLowEnergyController::error),
                this, &Device::errorReceived);
        connect(controller, &QLowEnergyController::disconnected,
                this, &Device::deviceDisconnected);
        connect(controller, &QLowEnergyController::serviceDiscovered,
                this, &Device::addLowEnergyService);
        connect(controller, &QLowEnergyController::discoveryFinished,
                this, &Device::serviceScanDone);
    }

    if (isRandomAddress())
        controller->setRemoteAddressType(QLowEnergyController::RandomAddress);
    else
        controller->setRemoteAddressType(QLowEnergyController::PublicAddress);
    controller->connectToDevice();

    m_previousAddress = currentDevice.getAddress();
}

void Device::addLowEnergyService(const QBluetoothUuid &serviceUuid)
{
    QLowEnergyService *service = controller->createServiceObject(serviceUuid);
    if (!service) {
        qWarning() << "Cannot create service for uuid";
        return;
    }
    auto serv = new ServiceInfo(service);
    m_services.append(serv);

    emit servicesUpdated();
}

void Device::serviceScanDone()
{
    setUpdate("Back\n(Service scan done!)");
    // force UI in case we didn't find anything
    if (m_services.isEmpty())
        emit servicesUpdated();
}

void Device::connectToService(const QString &uuid)
{
    QLowEnergyService *service = nullptr;
    for (auto s: qAsConst(m_services)) {
        auto serviceInfo = qobject_cast<ServiceInfo *>(s);
        if (!serviceInfo)
            continue;

        if (serviceInfo->getUuid() == uuid) {
            service = serviceInfo->service();
            break;
        }
    }

    if (!service)
        return;

    qDeleteAll(m_characteristics);
    m_characteristics.clear();
    emit characteristicsUpdated();

    if (service->state() == QLowEnergyService::DiscoveryRequired) {
        connect(service, &QLowEnergyService::stateChanged,
                this, &Device::serviceDetailsDiscovered);
        service->discoverDetails();
        setUpdate("Back\n(Discovering details...)");
        return;
    }

    //discovery already done
    const QList<QLowEnergyCharacteristic> chars = service->characteristics();
    for (const QLowEnergyCharacteristic &ch : chars) {
        auto cInfo = new CharacteristicInfo(ch);
        m_characteristics.append(cInfo);
    }

    QTimer::singleShot(0, this, &Device::characteristicsUpdated);
}

void Device::deviceConnected()
{
    setUpdate("Back\n(Discovering services...)");
    connected = true;
    controller->discoverServices();
}

void Device::errorReceived(QLowEnergyController::Error /*error*/)
{
    qWarning() << "Error: " << controller->errorString();
    setUpdate(QString("Back\n(%1)").arg(controller->errorString()));
}

void Device::setUpdate(const QString &message)
{
    m_message = message;
    emit updateChanged();
}

void Device::disconnectFromDevice()
{
    // UI always expects disconnect() signal when calling this signal
    // TODO what is really needed is to extend state() to a multi value
    // and thus allowing UI to keep track of controller progress in addition to
    // device scan progress

    if (controller->state() != QLowEnergyController::UnconnectedState)
        controller->disconnectFromDevice();
    else
        deviceDisconnected();
}

void Device::deviceDisconnected()
{
    qWarning() << "Disconnect from device";
    emit disconnected();
}

void Device::serviceDetailsDiscovered(QLowEnergyService::ServiceState newState)
{
    if (newState != QLowEnergyService::ServiceDiscovered) {
        // do not hang in "Scanning for characteristics" mode forever
        // in case the service discovery failed
        // We have to queue the signal up to give UI time to even enter
        // the above mode
        if (newState != QLowEnergyService::DiscoveringServices) {
            QMetaObject::invokeMethod(this, "characteristicsUpdated",
                                      Qt::QueuedConnection);
        }
        return;
    }

    auto service = qobject_cast<QLowEnergyService *>(sender());
    if (!service)
        return;

    const QList<QLowEnergyCharacteristic> chars = service->characteristics();
    for (const QLowEnergyCharacteristic &ch : chars) {
        auto cInfo = new CharacteristicInfo(ch);
        m_characteristics.append(cInfo);
    }

    emit characteristicsUpdated();
}

void Device::deviceScanError(QBluetoothDeviceDiscoveryAgent::Error error)
{
    if (error == QBluetoothDeviceDiscoveryAgent::PoweredOffError)
        setUpdate("The Bluetooth adaptor is powered off, power it on before doing discovery.");
    else if (error == QBluetoothDeviceDiscoveryAgent::InputOutputError)
        setUpdate("Writing or reading from the device resulted in an error.");
    else {
        static QMetaEnum qme = discoveryAgent->metaObject()->enumerator(
                    discoveryAgent->metaObject()->indexOfEnumerator("Error"));
        setUpdate("Error: " + QLatin1String(qme.valueToKey(error)));
    }

    m_deviceScanState = false;
    emit devicesUpdated();
    emit stateChanged();
}

bool Device::state()
{
    return m_deviceScanState;
}

bool Device::hasControllerError() const
{
    return (controller && controller->error() != QLowEnergyController::NoError);
}

bool Device::isRandomAddress() const
{
    return randomAddress;
}

void Device::setRandomAddress(bool newValue)
{
    randomAddress = newValue;
    emit randomAddressChanged();
}